The present disclosure relates to a sheet discharge device configured to discharge sheets onto a sheet tray, and an image forming apparatus provided with the sheet discharge device.
An image forming apparatus such as a copying machine, a printer, a facsimile machine, or a complex machine provided with the functions of these machines is provided with a sheet tray on which sheets each carrying an image are discharged. A sheet carrying an image is discharged onto a sheet tray by a discharge roller disposed above the sheet tray.
In the case where a sheet is curled, a trailing end of the sheet discharged from the discharge roller may be stuck on a wall surface below the discharge roller. In view of the above, there is known a technique such that a sheet is allowed to come into contact with an end of a plate-shaped member at a position inwardly away from widthwise ends of the sheet by a certain distance for pressingly contacting the sheet with the discharge roller. In the case where a sheet having a relatively small stiffness such as thin paper is passed, however, the sheet may be stuck by the plate-shaped member, or the sheet may be undulated due to pressing contact. Further, at the time of double-sided printing, an end of the plate-shaped member may come into pressing contact with an image surface of the sheet with a large force, which may result in poor image formation.
Further, in the background art shown in FIG. 14, a plate-shaped pressing member X1 is disposed to come into contact with the outer surface of a discharge roller X2 in a direction from above the discharge roller X2 obliquely downwardly in a sheet discharge direction. A trailing end of a sheet discharged from the discharge roller X2 is guided downwardly along the plate-shaped pressing member X1. However, in the above configuration, there is a space between the pressing member X1 and the discharge roller X2 at a position lower than the position where the pressing member X1 comes into contact with the discharge roller X2. As a result, if a sheet having an upwardly curled trailing end is discharged, the trailing end of the sheet enters the space between the pressing member X1 and the discharge roller X2. This may make it difficult or impossible to guide the trailing end of the sheet to a position below the discharge roller X2 by the pressing member X1. As a result, a next sheet P to be discharged may be guided to a position beneath the preceding sheet P. Further, in the case where a sheet having a downwardly curled leading end is discharged, the downwardly curled portion of the sheet may press the pressing member further downwardly. This may cause the leading end of the sheet to come into contact with the bottom portion of the sheet tray with a large angle. Consequently, the leading end of the sheet may be curled up on the sheet tray.
An object of the present disclosure is to provide a sheet discharge device that enables to discharge a sheet onto a sheet tray in a satisfactory manner, no matter in which direction the sheet is curled, and an image forming apparatus provided with the sheet discharge device.